radio-frequency matters

WMO CBS-ISS 21 September 2006 1

Radio-Frequency Matters

Philippe TRISTANT

([email protected])

Frequency Manager of Météo France

Chairman of the Steering Group on Radio Frequency Coordination (SG-RFC)


Radio Frequencies• Radio-Frequency represent scarce and key resources for

the meteorological community• stressed in WMO Resolution 3 SG-RFC(Cg‑XIV) – Radio

frequencies for meteorological and related environmental activities –

• radiocommunications are moving fast and there is a huge and increasing pressure on the whole spectrum from the industry representing huge economical an political interests

• This could potentially put at risk the whole meteorological process

• Justifying a global and increased involvement of the meteorological community in frequency matters to safeguard interests


SG-RFC• Last SG-RFC was held 16-17 March 2006• Meeting Report is available at :

http://www.wmo.int/web/www/TEM/SG-RFC06/documents.html

• On short, the meeting :– Made a general review of all issues related to radio-frequency,

recognising the increasing pressure on corresponding frequency bands

– Supported the WMO implication in the GEO task on frequency (AR-06-11)

– Noted the new issue on potential impact of wind-farms on radars

– Adopted the preliminary WMO positions on World Radiocommunication Conference 2007 (WRC-07) agenda


Workshop• Following last SG-RFC, WMO organised a Workshop 20-21

March 2006• The aim of this Workshop was to present the frequency issues

to a larger number of WMO members as well as some outside organisations (ITU and European Commission in particular)

• General and detailed presentations were ensured, in particular on presenting the WMO position related to WRC-07 :http://www.wmo.int/web/www/TEM/RF-W-2006/workplan.html

• Workshop was highly appreciated from both members and outside organisations

• It was recognised that for next Workshop, enlarging outside invitation could help advertising both our frequency uses and requirements


SG-RFC and Workshop Message• WMO is able to raise positions and concerns to international

bodies in charge of Frequency management• Our action is sometimes limited by the fact that Frequency

issues are handled by National Radio Authorities (NRA)• NRA are in general not aware of the specific use of radio-

spectrum by meteorological community and in particular obligations under the WWW

• Each National Meteorological service needs to get involved by :– Contacting its NRA to relay our positions and

concerns– providing SG-RFC all relevant information

pertaining to their national situation


WRC-07• WRC-07 is schedule 22 October – 16 November in

Geneva• The Conference Preparatory Meeting (CPM) will meet in

Geneva 5-16 March 2007• 7 items concern frequency bands or issues of prime

interest for Meteorology • 5 items do not directly concern meteorological interests

but might have an impact on frequency bands used for meteorological purposes


WRC-07 agenda items of prime interest• agenda item 1.2 : Extension of the 18 GHz METSAT allocation and

protection of the 10.7 and 36 GHz EESS (passive) bands• agenda item 1.3 : Upgrading and protection of radiolocation in

the 9 GHz range, and 200 MHz extension of the Earth exploration satellite service (EESS) allocation at 9500-9800 MHz

• agenda item 1.4 : Impact on meteorological radars related to future frequency bands for IMT-2000

• agenda item 1.12 : Coordination and notification procedures for Earth Exploration Satellite Service (EESS) (active and passive) sensors

• agenda item 1.17 : Protection of the 1.4 GHz EESS (passive) band• agenda item 1.20 : Unwanted emissions in EESS (passive) bands• agenda item 7.2 : WRC-10 agenda (bands above 275 GHz)


Other WRC-07 agenda items of interest• agenda item 1.5 : Possible additional allocations for

aeronautical telecommand and high bit-rate aeronautical telemetry between 3 and 30 GHz

• agenda item 1.6 : Additional allocations for Aeronautical Mobile Service between 108 MHz and 6 GHz

• agenda item 1.8 : High Altitude Platform Stations (HAPS) in the 28 and 31 GHz band

• agenda item 1.18 : Pfd limits for Highly Elliptical Orbit (HIO) satellites in the frequency band 17.7-19.7 GHz

• agenda item 1.19 : Internet satellite applications


Agenda item 1.2 (WRC-07)“to consider allocations and regulatory issues related to the Earth exploration-satellite (passive) service, space research (passive) service and the meteorological satellite service in accordance with Resolutions 746 (WRC-03) and 742 (WRC-03)”

3 issues related to meteorological applications :

– Issue 1 : protection of the passive band 36-37 GHz

– Issue 2 : extension of the 18.1-18.3 GHz METSAT allocation

– Issue 3 : protection of the passive band 10.6-10.68 GHz


Agenda item 1.2 (WRC-07)Issue 1 : protection of the passive band 36-37 GHz

– the band 36-37 GHz is vital for the study of global water circulation since this band is able to monitor the rain, the snow, the ocean ice and the water vapour for ocean and land surfaces

– A number of passive sensors and radio altimeters are already using or are planning to use this frequency band in the near future

– This band is shared with active services (Fixed and Mobile) that may interfere passive measurements if transmitting at high power

WMO supports the protection of the 36-37 GHz passive bands and believes that identification of the maximum e.i.r.p and power for fixed and mobile links could provide a means to ensure such a protection.


Agenda item 1.2 (WRC-07)Issue 2 : extension of the 18.1-18.3 GHz METSAT allocation at 18 GHz

– current allocation is given in RR footnote 5.519 (18.1 -18.3 GHz)– Not sufficient to fulfil the expected requirements of next generation

geostationary METSAT (2015-2020) :• UV and IR sounding• Higher resolution and repetition rate

– 2 options for the extension:• 18.0 -18.1 GHz : political issues in relation with the appendix 30A BSS plan• 18.3 -18.4 GHz : few countries intend to use this band for high density FSS

WMO is of the view that such extension will not constrain existing services provided that the same regulatory conditions as in the 18.1-18.3 GHz band (e.g. Article 21 pfd limits) are applied. WMO does not favour one of the options over the other (18-18.1 GHz band or 18.3-18.4 GHz band) but believes that a worldwide allocation in a single band would be preferred.


Agenda item 1.2 (WRC-07)Issue 3 : protection of the passive band 10.6-10.68 GHz– the band 10.6-10.7 GHz is of primary interest to measure rain, snow, sea

state and ocean wind for ocean and land surfaces – A number of passive sensors and radio altimeters are already using or are

planning to use this frequency band in the near future – The band 10.68-10.7 GHz is covered by RR footnote 5.340 (all emissions

are prohibited)– The band 10.6-10.68 GHz is shared with active services (Fixed and Mobile)

with limits set in footnote 5.482 (40 dBW eirp and –3 dBW power)

WMO supports the protection of the 10.6-10.68 GHz passive bands (the band 10.68-10.7 GHz is covered under RR footnote 5.340). It should, however, be stressed that current deployments of FS links in certain administrations already create significant levels of passive measurement degradation in this band. Additional constraints on the 10.6-10.68 GHz passive band would hence not be acceptable and therefore, WMO strongly encourages the identification of the maximum power and eirp for fixed and mobile services that would protect EESS (passive) in the 10.6-10.68 GHz band.


Agenda item 1.2 (WRC-07)

RFI in unprotected band at 10.6 GHz over Europe and Japan.

From: Chris Kidd (Univ. Birmingham, UK)


Agenda item 1.3 (WRC-07)“in accordance with Resolution 747 (WRC-03), consider upgrading the radiolocation service to primary allocation status in the bands 9 000-9 200 MHz and 9 300-9 500 MHz and extending by up to 200MHz the existing primary allocations to the Earth exploration-satellite service (active) and the space research service (active) in the band 9 500-9 800 MHz without placing undue constraint on the services to which the bands are allocated”

Meteorological radars in the 9300-9500 MHz are currently seen as the adequate solution to improve the coverage of the radar networks deployed in the 2.8 and 5.6 GHz bands

2 issues related to meteorological applications :– Issue 1 : upgrading the radiolocation status in the 9300-9500 MHz band– Issue 2 : Sharing between meteorological radars and EESS (active) in

the 9300-9500 MHz band


Agenda item 1.3 (WRC-07)Issue 1 : upgrading the radiolocation status in the 9300-9500 MHz band

– the radiolocation service is currently secondary (no interference – no protection)

– RR footnote 5.475 states that “In the band 9300-9500 MHz, ground-based radars used for meteorological purposes have priority over other radiolocation devices”

– Current meteorological radars have been deployed without adverse impact on Radionavigation service

– General support in ITU-R to allow for upgrading to primary but some countries wish to add a “no interference – no protection” footnote (de facto secondary)

WMO supports the upgrade to primary of Radiolocation Service in the band 9 300-9 500 MHz on an equal footing with Radionavigation Service retaining (either in the current or new footnote) the provisions of RR 5.475 that addresses meteorological radars.


Agenda item 1.3 (WRC-07)Issue 2 : sharing with EESS (active) in the 9300-9500 MHz band

– EESS (active) currently allocated in the 9500-9800 MHz band– Need expressed for a 200 MHz extension to cover Synthetic Aperture Radars

(SAR)– Current studies show that SAR may interfere with meteorological radars, but

on a very short term– There is a wide consensus in the ITU-R in line with WMO position

Subject to final studies showing that the potential interference impact to meteorological radar operations is insignificant, WMO could support extension to the band 9 300-9 500 MHz of the EESS (active) and the space research service (active) allocations. The present RR footnote 5.476A would also need to be extended to this band. Also, WMO is of the view that, to limit the risk of interference, such extension should be limited to EESS (active) systems that needs a bandwidth higher than the current 300 MHz allocation. Should EESS (active) and space research service (active) allocations not be possible in the lower band, WMO could also support such allocations in the 9800-10000 MHz band.


Agenda item 1.4 (WRC-07)““to consider frequency-related matters for the future development of IMT‑2000 and systems beyond IMT‑2000 taking into account the results of ITU‑R studies in accordance with Resolution 228 (Rev. WRC-03)”

2 bands of interest for the meteorological community are currently considered for IMT-2000 identification :– 2700-2900 MHz band : meteorological radars– 5150-5725 MHz : EESS (active) in the 5250-5350 MHz and

5470-5570 MHz bands and meteorological radars in the 5470-5650 MHz band

The case of the band 3400-3800 MHz for satellite communications also needs to be stressed


Agenda item 1.4 (WRC-07)– The issue of the 2700-2900 MHz band was already considered in

preparation of WRC-2000– Despite studies showed that sharing is not feasible, a number of

administrations are putting pressure on this band and propose to limit IMT to some kind of applications presenting less constraints !

– The 5 GHz band was considered by the WRC-03 that allocated the band to the Mobile service, limited to RLAN, with a number of specific constraints to protect radars and EESS (active)

– IMT-2000 (nomadic) may be identified under the RLAN constraints– In the too cases, there is also a high risk that once identified for IMT-

2000, future initiative be made to relax or withdraw current limitations (see agenda item 1.9)

Keeping in mind studies in the 2700-2900 MHz prior to WRC-2000 that already concluded on the non compatibility between IMT-2000 and radars, WMO is strongly opposed to any IMT-2000 identification in the 2700-2900 MHz and 5250-5650 MHz bands.


Agenda item 1.4 (WRC-07)Interference to 5 GHz radars from RLAN

Poland

Hungary


Agenda item 1.20 (WRC-07)“to consider the results of studies, and proposals for regulatory measures, if appropriate, regarding the protection of the Earth exploration-satellite service (passive) from unwanted emissions of active services in accordance with Resolution 738 (WRC-03)”

– Highly sensitive and political issue, on the agenda of the last 3 WRCs

– Concerns the main passive bands covered in RR footnote 5.340 (All emissions are prohibited)

– Technical work to determine the adequate out-of-band levels– Regulatory issue on whether or not to include these levels in the

RR

WMO supports appropriate regulatory measures in the Radio Regulations to ensure the protection of the Earth exploration satellite service (passive) from unwanted emissions. Such measures should minimize the burden on the relevant active services but the protection of the related passive bands should be a prerequisite


Agenda item 7.2 (WRC-07)– Concern the preparation of the next WRC (2010/2011)– The Preliminary agenda for the 2010 World Radiocommunication

Conference already includes the following item :to consider frequency allocations between 275 GHz and 3 000 GHz taking into account the result of ITU-R studies in accordance with Resolution 950 (WRC‑03); The issue of the 2700-2900 MHz band was already conisdered in preparation of WRC-2000

– Passive sensing present direct interest for meteorological community (already few operational sensors)

– Early assessment would be welcomed but there is a lack of knowledge concerning active services

WMO supports either the retention of agenda item 2.2 (WRC-10) or, as an alternative, consideration of a modified agenda item that would propose to review and revise RR footnote 5.565 to update the uses of the spectrum from 275 to 3 000 GHz by the Earth exploration-satellite (passive), radio astronomy, and space research (passive) services.


WMO output and actions for WRC-07

• SG-RFC has issued Preliminary WMO positions that have been sent to ITU-R

• WMO was represented (by SG-RFC members) and contributed within ITU-R groups

• WMO secretariat will soon distribute these positions to all WMO members encouraging them to advertise to a large extent these positions, in particular to their NRA

• A revised version of WMO positions will be prepared prior to the CPM to take advantage of recent ITU-R discussions

• Also, the possibility to organise a Workshop during CPM (targeting on Radio Administrations) is under consideration

• WMO representation and contributions will be ensured for WRC-07, but detailed organisation yet to be defined


Generic UWB applications

• new technology for civil applications using bandwidth of several GHz and transmits at very low power (mainly below 10 GHz but also Automotive radars at 24 GHz)

• could represented a serious threat for meteorological applications, in particular passive bands as well as meteorological radar (S, C and X bands)

• WMO has been heavily involved in this issue in ITU-R TG 1/8 either on a European or international basis

• Satisfactory outcomes, even though some administrations may not (or have not) follow the Recommendations

• The final results in Europe are totally satisfactory since all meteorological bands are protected (UWB will be focusing in the 6-8.5 GHz and possibly in the 3-5 GHz bands)

• SG-RFC will issue a summary on UWB issues


Spectrum Overview

0 1 2 3 4 5 6 7 8 9 10 11

F (GHz)

Radiosondes and wind profilers

Wind profilers

1400-1427 MHz passive band

Radiosondes and METSAT

Weather radars

EESS (active) 6.7-7.1 GHz passive band

Weather radars

EESS (active) METSAT

10.6-10.7 GHz passive band

Weather radars

GPR/WPR and imaging UWB devices

Communications and location tracking UWB devices


Public consultations• SG-RFC, has initiated a work to respond public

consultations issued by radiocommunication bodies (National or Regional)

• Responses are prepared by correspondence

– Response to the Australian Administrations on a Decision related to SRR 24 GHz and RLAN 5 GHz : negative and positive outcomes

– Response to the European Commission on a high level “Opinion” related to scientific use of the spectrum : positive outcomes


Handbook• The joint ITU/WMO handbook on “Use of radio spectrum

for Meteorology” is widely recognised as an important tool for understanding our specific applications

• It was issued in 2002 and certainly needs an update• SG-RFC is currently working on a revision, targeting a

release prior WRC-07• Work is on-going since about 1 year and a specific SG-

RFC meeting was organised 4th September


GEO• From the beginning, WMO is involved in GEO and in

particular with regards to the protection of radio-frequencies

• When GEO Task related to radio-frequency (AR-06-11) has been adopted, WMO evidently proposed itself to lead this task according to its current involvement in frequency management and in particular its ability to further positions at ITU-R level

• SG-RFC chairman is now the Point of Contact (POC) of this task

• Work is in progress and a general GEO “Resolution” will be prepared


Economical and societal impact• Facing powerful radio lobbies representing huge

economical impacts, radiocommunication administrations are more and more undertaking “impact” analysis of the use of each frequency bands

• The meteorological applications are not exonerated• SG-RFC has decided to draft a general document

stressing societal and economical impacts of meteorology in the light of spectrum use

• It will build upon in particular on materials presented during the discussions at European Commission levels (UK Metoffice, WMO,…),

• All other information from members will be welcomed


Wind farms issue– In front of huge pressure and potential deployment of

Wind farms, Meteo France has undertaken technical studies to determine their impact on meteorological radars *:• Blocking• Clutter• Doppler effect

– These studies, confirmed by testing, shows that the worst impact is on Doppler, due to tremendous reflections on wind mills (RCS up to 30 dBsm)

– Led to a specific report in France recommending exclusion (5 and 10 km) and coordination (20 and 30 km) distances for C and S band meteorological radars**

* similar studies are on-going in the US** Similar recommendations are also made for Civil aviation and military radars


Evolution de la porte 112 ( correspondant à 17 km du radar)

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Wind farms responses on side lobes

Wind farms issueWind farms responseson main beam

• Wind farms at 17 km

• Direct response without filtering

• Over 90° Azimuth• Confirms huge

response and equivalent RCS of about 23dBsm

• Highlight the huge impact over radar side lobes (radar sensitivity at about –15 dBz at 17 km)

• And hence the Doppler impact


Future work• SG-RFC will meet in 2007 prior the CPM tentatively mid

January in the US (TBC)• Another meeting will certainly be organised prior the WRC• Of course, correspondence group is active that allows

discussions in interim period• This is in particular important for preparing contributions

and attendance to ITU-R meeting and in particular :– Working Party 8B (radars)– Working party 7B and 7C (meteorological applications)

• this is of the utmost importance that WMO be represented (Either by Secretariat or SG-RFC members) each time meteorological interests are discussed


Conclusions• Radiofrequency matters is increasingly strategic for the

meteorological community,• Currently, apart radiosondes, all spectrum usages

related to the meteorological process are under threats, and in particular passive bands

• Global involvement from WMO and members is mandatory, at national and international levels

• SG-RFC is of course totally open for any details and support

Thank you for your attention

radio-frequency matters

Documents

frequency issues

frequency ar

future frequency bands

meteorological community

meteorological interests

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meteorological process

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